# Coprime facts for kids

In mathematics, two integers (*a* and *b*) are **co-prime** (or **relatively prime**) if they share no common factors. This is sometimes written as . In other words, there is no number, other than 1, that divides both a and b evenly. In which case, the greatest common divisor (**GCD**, or **highest common factor**) of these numbers is 1.

As an example, 6 and 35 are coprime, because the factors of 6, 2 and 3, do not divide 35 evenly. On the other hand, 6 and 27 are not coprime, because 3 divides both 6 and 27. Another example is 4 and 5: 4 = 2*2*1; 5 = 5*1 (Prime). The only common factor is 1, so they are coprime.

On the other hand, 10 and 5: 10 = 5*2 5 = 5*1 (Prime). The common factors are 5 and 1, so they are not coprime.

Prime numbers are always **coprime** to each other.

- Any two consecutive integers are always
**coprime**. - Sum of any two
**coprime**numbers is always**coprime**to their product. - 1 is trivially
**coprime**with all numbers. - if out of two numbers, any one number is a prime number while the other number is not a multiple of first one, then both are coprime.
- This is not applicable to negative numbers

## Related pages

## See also

In Spanish: Números coprimos para niños

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